In previous columns, we
explained that Strike Doubling is generally accepted to be created by looseness
in the press, which in turn causes vibrations to set up during the coining
operation.This may cause the upper
die to bounce against the struck coin a split second after it is struck
resulting in an area of the field parallel to a design (on the die) smashing
down a section of raised designs on the coin.Depending on the orientation of the coin on the lower die, (which may
shift slightly during ejection) this flat shelf of doubling that borders one
side of raised design elements may be found on the obverse and/or reverse and is
usually what researchers point to as an
identifying diagnostic of strike doubling.

However, in our previous
treatments of this subject we have examined variations from this flattened to the field rule,including doubling formed as a design is smashed down a slope, how some
design elements in the field that closely border a design may be are raised up into
another design area during die bounce, and the effect of a die that slides and
pushes metal up the side of a design.

This month we examine a 1984-D
Olympic Dollar sent in by Jeffrey Vasington of CT.The doubling on the date and legend bordering the lower rim
is outrageously strong and it appears to be a classic example of hub doubling
complete with separation lines between the doubled images and a strong notching
effect in their corners.Conspicuously
absent is the flat shelf-like type of damage typical of strike doubling.

They say: if it walks like a
duck and quacks like a duck, then it must be a duck.Thus the doubling shown here must be hub doubling! Right?Wrong!It's
Strike doubling!While the doubling
seems to break all the rules of what we have learned to expect strike doubling
to look like, the answer is simple and easy to understand.

Unlike the majority of coins
that boast raised images, the effected elements noted above are incuse designs
on this coin and are thus raised on the die.Since they are raised on the die, any bouncing of this portion of the die
into the coin will be exactly like a hub or punch sinking images into a die
blank!The result is an effect
exactly like that found on a doubled die
yet it is simply another manifestation of strike doubling
as form of damage that adds no value to a coin!

Other design areas on the coin
that are raised in the typical fashion we are used to encountering on U.S.
coins, such as the Mint Mark; L of LIBERTY and IN of IN GOD WE TRUST, exhibit
typical flattened down strike doubling.

Ken
Potter is the official attributor of world doubled dies for the Combined
Organizations of Numismatic Error Collectors of America and for the National
Collectors Association of Die Doubling.He
also privately lists other collectable variety types on both U.S. and world
coins in the Variety Coin Register.More
information on either of the clubs or how to get a coin listed in the Variety
Coin Register may be obtained by sending a long self addressed envelope with 99c
postage or by contacting him via email at KPotter256@aol.comAn educational image gallery may be viewed on his website at www.koinpro.com

Who Is Ken Potter?Unless otherwise stated, all Photographic Images are by Ken
Potter. Copyright Ken Potter, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
2002. Use of images in any manner is strictly prohibited without the express written
permission of the copyright holder.